02853nas a2200229   4500008004100000022001400041245014600055210006900201260006900270300001200339490000800351520198800359653001902347653001502366653001902381653001902400653001902419100002202438700002102460700001802481856012402499       2011                        eng d  a0254-058400aRole of lattice defects and crystallite morphology in the UV and visible-light-induced photo-catalytic properties of combustion-prepared TiO20 aRole of lattice defects and crystallite morphology in the UV and  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcAPR  a546-5540 v1263 a<p>The physico-chemical, photo-physical and micro-structural properties responsible for the strikingly different photocatalytic behavior of combustion-prepared TiO2 (c.TiO2) and Degussa P25 (d.TiO2) samples are elucidated in this study. Electron microscopy and selected area electron diffraction micrographs revealed that the two samples exhibited different morphologies. The grains of c.TiO2 were spherical and comprised of 5-6 nm size primary particle. On the other hand, d.TiO2 consisted of large (0.5-3.0 mu m) size and irregular shape aggregates having primary particles of 15-40 nm cross-sectional diameter. The ESR study revealed that the presence of certain defect states in c.TiO2 helped in stabilization of O-. and Ti3+-OH type species during room-temperature UV-irradiation. No such paramagnetic species were however formed over d.TiO2 under similar conditions. C1s and Ti 2p XPS spectra provide evidence for the presence of some lattice vacancies in c.TiO2 and also for the bulk Ti4+ -&gt; Ti3+ conversion during its UV-irradiation. Compared to d.TiO2, c.TiO2 displayed considerably higher activity for discoloration of methyl orange but very poor activity for splitting of water, both under UV and visible light radiations. This is attributed to enhanced surface adsorption of dye molecules over c.TiO2, because of its textural features and also the presence of photo-active ion-radicals. On the other hand, the poor activity of c.TiO2 for water splitting is related to certain defect-induced inter-band charge trapping states in the close vicinity of valence and conduction bands of c.TiO2, as revealed by thermoluminescence spectroscopy. Further, the dispersion of nanosize gold particles gave rise to augmented activity of both the catalysts, particularly for water splitting. This is explained by the promotional role of Au-0 or Au-0/TiO2 interfacial sites in the adsorption and charge-adsorbate interaction processes. (C) 2011 Elsevier B.V. All rights reserved.</p>10aBand-structure10aInterfaces10aMicrostructure10aNanostructures10aSemiconductors1 aDeshpande, Aparna1 aMadras, Giridhar1 aGupta, N., M.  uhttps://library.ncl.res.in/content/role-lattice-defects-and-crystallite-morphology-uv-and-visible-light-induced-photo-002032nas a2200217   4500008004100000022001400041245013700055210006900192260010600261300001400367490000700381520115400388653002501542653002301567653002401590653001501614653001901629100002101648700001801669856012701687       2012                        eng d  a0025-540800aEffects of grain morphology, microstructure and dispersed metal cocatalyst on the photoreduction of water over impurity-doped LaInO30 aEffects of grain morphology microstructure and dispersed metal c  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAY  a1217-12280 v473 a<p>The single phase lanthanum indates doped with Ga (for La) and N (for O), i.e. La1-xGaxInO3 (0 &lt;= x &lt;= 0.2) and LaInO1-yNy (y similar to 0.6), exhibit significant activity for photoreduction of water; the yield of H-2 produced depending on dopant, excitation source, and addition of a sacrificial reagent. The two-step H-2 evolution observed for this reaction corresponds with the two distinct absorbance regimes displayed by these materials, one in UV-region due to bandgap excitation and the other in visible region arising from the transitions involving sub-bandgap donor or acceptor energy states. The photocatalytic activity of these d(10) metal oxides increases on coating with a metal/metal oxide co-catalyst, gold exhibiting superior activity to Pt and NiO, irrespective of excitation source and sample composition. The preparation-controlled particle morphology, doping-induced lattice imperfections, and metal/semiconductor hetero-junctions are envisaged to play a key role in the absorption characteristics and photocatalytic water reduction activity of metal/LaInO3 nanocomposites. (C) 2012 Elsevier Ltd. All rights reserved.</p>10aCatalytic properties10aChemical synthesis10aElectron microscopy10aInterfaces10aSemiconductors1 aDhanasekaran, P.1 aGupta, N., M.  uhttps://library.ncl.res.in/content/effects-grain-morphology-microstructure-and-dispersed-metal-cocatalyst-photoreduction-0